1. Field of the Invention
The present relates to a headrest provided on an automotive seat, and particularly to an arrangement and method for securing a headrest stay in the seat.
2. Description of Prior Art
In an integral foamed seat back construction, it has been common to use a cylindrical die to form a pair of holes for receiving a pair of headrest stay dependent from a headrest body. In this seat back forming process, a seat back frame having a pair of headrest stay holders provided on its upper frame section is placed in a mold, then two cylindrical dies are fully inserted in such pair of headrest stay holders, respectively, down to the lower ends of the headrest stay holders, after which, a foamble base material in liquid form is injected into the mold to carry out a foaming together with the seat back frame, and after the foaming step, the two cylindrical dies are taken out from the respective headrest stay holders. Thus, an integral seat back body with opened pair of headrest stay holders is obtained, which allows insertion of the two headrest stays into the respective stay holders.
This kind of seat back is shown in FIG. 1, as designated by (SB). The seat back (SB) is formed in the above-described foaming way into an integral body comprising a foam cushion member (1), a seat back frame (2) embedded in the cushion member (1), a pair of spaced-apart headrest stay holders (3)(3) fixed on the upper frame section of seat back frame (2), and a covering member (8) affixed over the cushion member (1). A headrest (HR) is provided upon the seat back (SB) such that a pair of spaced-apart headrest stays (5)(5) dependent from the headrest (HR) are inserted into the foregoing pair of headrest stay holders (3)(3), as shown.
However, if a strict tolerance is set between the spacing (L1) of the two headrest stays (5)(5) and that (L2) of the stay holders (3)(3), the stays (5)(5) will not easily be inserted into the holders (3)(3), or alternatively if a rough design is made in this regard, the stays (5)(5) will not be fit settled in the holders (3)(3), resulting in wobbling of the stays (5)(5) and thus of the headrest (HR).
To solve such problem, the Japanese Utility Model Publication No. 2-19347 suggests provision of a leaf spring in each of headrest stay holders. The leaf spring resiliently bias a heardrest stay into contact with the inner surface of the stay holder, thereby compensating for a play created between the headrest stay and stay holder and eliminating the wobbling of the stay in the holder. But, this arrangement is rather complicated, and the leaf spring is hard to be mounted in the stay holder, requiring a certain expertise or troublesome steps for assemblate of the seat.